This invention relates generally to a system for autonomous excavation and, more particularly, to a system for performing excavation and loading tasks with an autonomous excavating machine.
Machines such as excavators, backhoes, front shovels, and the like are used for earthmoving work and operations. These earthmoving machines typically have work implements which consist of boom, stick, and bucket linkages. The boom is pivotally attached to the excavating machine at one end and to its other end is pivotally attached a stick. The bucket is in turn pivotally attached to a free end of the stick. Each work implement linkage is controllably actuated by at least one hydraulic cylinder for movement in a vertical plane. An operator manipulates the work implement to perform a sequence of distinct functions which constitute a complete earthmoving cycle within an earthmoving operation.
One type of machine commonly found at an earthmoving site is an excavator that is positioned above a pile of material to be removed. In a typical work cycle of an excavator, the operator uses prior experience to determine an optimal location to excavate and positions the work implement at the determined location. The operator then lowers the work implement downward until the bucket penetrates the soil and executes a digging stroke which brings the bucket toward the excavating machine. The operator subsequently curls the bucket to capture the soil. To dump the captured load the operator raises the work implement, swings it transversely to a specified dump location, such as a dump truck, determines the optimal location to place the load for the desired distribution within the dump location, and releases the soil by extending the stick and uncurling the bucket. The work implement is then returned to the trench location to repeat the work cycle.
Another type of machine commonly found at an earthmoving site is a front-end loader that is often positioned facing a pile of material to be removed. A typical work cycle for a front-end loader differs somewhat from the work cycle for an excavator. With a front-end loader, the operator first determines an optimal location for removing material from the pile and lowers the bucket of the work implement to the ground before moving toward the selected location. The operator penetrates the material with the bucket and executes a digging stroke which raises the bucket upward through the material. The operator subsequently raises the work implement and tilts the bucket toward the loader to capture the material. To dump the captured load, the operator reverses the machine away from pile, determines the location for unloading the material, moves forward to the selected dump location, and releases the soil by tilting the bucket downward. The work implement is then reversed from the loading receptacle and returns to the pile of material to begin the work cycle again.
There is an increasing demand in the earthmoving industry to automate the work cycle of an excavating machine for several reasons. Unlike a human operator, an automated excavating machine remains consistently productive regardless of environmental conditions and prolonged work hours. Automated or autonomous earthmoving machines are ideal for applications where conditions are unsuitable or undesirable for humans. An automated machine also enables more accurate excavation and compensates for lack of operator skill or experience.
The major components for automating excavation include such steps as digging material, loading material into loading receptacles, and recognizing loading point positions and orientations throughout the excavation process. A system is needed to consolidate and coordinate the numerous components and tasks required for autonomous earthmoving machines in order for such machines to operate as efficiently as possible. This may be accomplished using a sensor system capable of providing up-to-date data pertaining to different portions or locations within the earthmoving environment. The system should include such components as a planning and control module implemented on a computer that uses the up-to-date data to concurrently plan and execute one or more portions or steps of the earthmoving task. It is also desirable for the system to use the sensor data to detect mobile and stationary obstacles in the earthmoving environment to allow adequate time for the various planning and executing components to respond accordingly. Further, it is desirable for the planning and control module to incorporate heuristics from expert operators in determining and performing an excavation strategy.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.
In accordance with the present invention, a system for autonomous control of an earthmoving machine within an earthmoving environment comprises an earthmoving machine equipped with a scanning sensor system operable to provide data regarding regions within an earthmoving environment including an excavation region and a loading region and a planning and control module operable to receive data from the scanning sensor system to plan a task associated with the control of the earthmoving machine while concurrently performing another task associated with control of the earthmoving machine.
Another form of the present invention is a system for autonomous control of an earthmoving machine with the system comprising an earthmoving machine equipped with a scanning sensor system operable to provide data corresponding to regions within an earthmoving environment including an excavation region and a loading region, a planning and control module operable to receive data from the scanning sensor system to plan a task associated with the control of the earthmoving machine in the excavation region while concurrently performing another task associated with control of the earthmoving machine within the loading region, and an obstacle detector for detecting the presence of an obstacle within the earthmoving environment and for generating a signal to halt operation of the earthmoving machine once the obstacle has been detected.
In another form of the present invention a system for autonomous control of earthmoving machinery is disclosed which comprises an earthmoving machine equipped with a scanning sensor system operable to provide data corresponding to regions within an earthmoving environment including an excavation region and a loading region, the scanning sensor system comprising a first sensor being operable to rotate to scan a field of view greater than zero degrees in a first plane around the earthmoving machine and a second sensor being operable to rotate to scan a field of view greater than zero degrees in a second plane around the earthmoving machine, the sensors being positioned on the earthmoving machine and having independently adjustable fields of view and scan patterns to provide range data for different areas of the earthmoving environment for planning and executing at least one earthmoving task and an obstacle detector operable to receive data from the scanning sensor system to determine if an object is present within the earthmoving environment and once an obstacle has been detected for halting operation of the earthmoving machine.